KR20160116376A - Releasing film for polarizing plate, and polarizing plate comprising thereof - Google Patents

Abstract

The present invention relates to a releasing film for a polarizing plate, and a polarizing plate comprising the same. More particularly, the present invention relates to a releasing film for a polarizing plate which has surface slip strength with an adhesive layer, 2 to 5 N/15 m, and a polarizing plate comprising the same. The releasing film according to the present invention relaxes the residual stress between the adhesive layer and the release film in a cutting process, prevents the stain and floating phenomenon of the polarizing plate, and improves the process margin of the polarizing plate.

Description

[0001] The present invention relates to a releasing film for a polarizing plate,

The present invention relates to a release film for a polarizing plate capable of increasing the process margin of the polarizing plate and a polarizing plate having the same.

BACKGROUND ART A flat panel display such as a liquid crystal display (LCD) and an organic light emitting diode (OLED) is composed of a large number of optical films made of a synthetic resin or an optical resin plate, have.

Unpolarized light emitted from the light source of the flat panel display is incident on the liquid crystal cell only by the linearly polarized light through the polarizing plate, and the intensity of the transmitted light is adjusted according to the degree of rotation of the polarization axis of the incident light and gray scale representation between black and white is possible . That is, the polarizing plate is one of the key materials for visually confirming the image implemented in the flat panel display.

The polarizing plate is manufactured through a stretching process and has a structure in which a transparent protective film is laminated on both sides or one side of a polarizer made of a polyvinyl alcohol based resin in which a dichroic dye is adsorbed and oriented. The polarizing plate is bonded to the panel of the display device by a pressure-sensitive adhesive layer.

1 is a cross-sectional view schematically showing a polarizing plate. 1 (a), a surface protecting film 17 for protecting the polarizing plate 15 is attached to one side, a pressure-sensitive adhesive layer 13 for attaching the panel to the other side, and a releasing film 11 Respectively. It is produced in the form of rolls in the bonded state.

The polarizing plate roll is unrolled from the wound state and cut according to the size of the panel to which it is attached.

As a method of cutting the polarizing plate, the polarizing plate is joined to the release film by a method of cutting the polarizing plate into a sheet of the release film, that is, cutting by a so-called full cut, or cutting by leaving only the laminated release film, There is a method of cutting the film by a so-called half cut.

The cutting is generally performed by a laser device, a cutter (e.g., Fine Chip Cutting, a rotary circular cutter) or other known cutting means, and is generally cut with a cutter 51 as shown in Fig. 1 (a).

After the polishing step of milling the edges of each of the polarizing plates cut by the cutting step, the polarizing plates are inspected with the naked eye, and then the respective products are packed in a pack The product will be shipped.

As shown in Fig. 1 (b), since the film is curved by the cutter 51 during the cutting process, damage to the film of the polarizing plate 15 occurs There may be a case where a nap on the cut surface, lifting of the surface protective film 17, or cracking of the polarizer in the polarizing plate 15 due to heating or cooling, that is, a so-called crack, may occur.

Korean Laid-Open Patent Application No. 2012-0129752 suggests that a defect occurring during cutting can be suppressed by performing a cutting process by adjusting a traveling speed and a cutting speed to a certain level using a circular cutter.

In this patent, napping of the cut surface was suppressed to some extent, but it was impossible to remove the stain occurring in the polarizing plate by this method.

That is, stress is applied to the entirety of the polarizing plate by the cutter during the cutting step, and the stress in the cutting step is concentrated on the pressure-sensitive adhesive layer and the release film which have the weakest bonding force. This residual stress is caused by the bonding pressure at the time of producing the polarizing plate and the crosslinking and curing of the pressure-sensitive adhesive. As a result, the pressure-sensitive adhesive layer and the release film are detached once due to the cutter pressure in the cutting process. As a result, unevenness (unevenness or spots) occurs in the stretching direction of the polarizing plate as shown in FIG. 2, (Or streaks) of the pressure-sensitive adhesive layer and the release film occur.

In addition, the polarizing plate is stored at room temperature until the product is shipped. At this time, the water content in the polarizing plate increases to increase the moisture content of the disk, thereby causing contraction of the polarizer and swelling of the surface protective film or pressure-sensitive adhesive layer. Curl is generated in the polarizing plate due to the contraction and expansion, and the stress due to the curl affects the pressure-sensitive adhesive layer and the release film, and the generated stain gradually moves inward during storage of the polarizing plate, Which can not be used, greatly reducing the production margin of the polarizer.

Korean Patent Publication No. 2012-0129752

Therefore, the applicant of the present invention paid attention to the idea that when the residual stress applied to the polarizing plate is dispersed or relaxed in the cutting process, the occurrence of the stain can be reduced, and by controlling the physical properties between the adhesive layer and the release film, The inventors of the present invention have completed the present invention by confirming that the stress can be sufficiently alleviated and thus the occurrence of stains can be reduced to increase the production margin of the polarizing plate.

Accordingly, it is an object of the present invention to provide a release film for a polarizing plate capable of increasing the processing margin of a polarizing plate.

Another object of the present invention is to provide a polarizing plate to which the release film is attached.

In order to achieve the above object, the present invention provides a release film for a polarizing plate characterized in that the surface slip strength with the pressure-sensitive adhesive layer is 2 to 15 N / 15 m.

The surface slip strength is 2 to 5 N / 15 m.

Wherein the releasing film for the polarizing plate has a peeling force with respect to the pressure-sensitive adhesive layer of 0.035 to 0.040 N / 25 mm.

Further, the release film for a polarizing plate has a silicone release coating layer formed on one side of the base film.

The present invention also provides a polarizing plate to which the release film for polarizing plate is attached.

The release film according to the present invention can alleviate the residual stress between the pressure-sensitive adhesive layer and the release film in the cutting process, thereby preventing the unevenness and lifting of the polarizer, thereby increasing the process margin of the polarizer.

1 is a cross-sectional view showing a polarizing plate, in which (a) shows a state before a cutting step, and (b) shows a state after a cutting step.
Fig. 2 is a photograph showing the stain occurring in the polarizing plate.
3 to 5 are schematic views showing a method of measuring the surface slip strength according to the present invention.

The present invention controls the physical properties of a release film for a polarizing plate to increase the process margin of the polarizing plate.

The release film referred to in the specification of the present invention is also referred to as a release film, release release film, or separate film.

The residual stress in the pressure-sensitive adhesive layer and the release film caused by the cutting process performed in the production of the polarizing plate causes unevenness and lifting of the polarizing plate. These stains and excitations are more severe after the polarizer storage and increase the defective rate of the polarizer. Accordingly, in the present invention, the slip property between the pressure-sensitive adhesive layer and the release film is controlled in order to alleviate the residual stress. In this case, the good slip property means that the residual stress between the pressure-sensitive adhesive layer and the release film is so small that little speckling or lifting between the release film and the pressure-sensitive adhesive layer occurs. However, if the slip property is too good, the release film may not adhere well to the pressure-sensitive adhesive layer and slip (slip) may occur.

The slip property can be numerically expressed by the surface slip strength (N / mm) of the force (N) relative to the moving distance (mm).

The surface slip strength referred to herein means a value measured by peeling the release film laminated on the pressure-sensitive adhesive layer in a direction of 0 DEG at a speed of 1.0 m / min.

In this case, the high value of the surface slip strength means that the adhesive force of the releasing film to be attached to the pressure sensitive adhesive layer is high. In this case, there is a possibility of stain or lifting phenomenon, This means that the release film easily slips even under the force. In this case, there is a fear that the release film adheres to the pressure-sensitive adhesive layer.

The surface slip strength can be measured by the method disclosed in the present invention.

First, as in the configuration shown in Fig. 3, a polarizing plate 13 having a surface protective film 11 on one side and a pressure-sensitive adhesive layer 15 and a release film 17 on the other side is prepared.

Next, the polarizing plate was cut into a size of 15 mm x 130 mm (width * length) to prepare a sample.

Next, two upper and lower lines (arrow positions) are cut at a distance of 15 mm above and below the center of the specimen in the longitudinal direction.

Next, along the cut upper line, the cut is made from the side of the surface protective film 11 to the pressure sensitive adhesive layer 15.

Next, only the release film 17 is cut with a cutter along the cut bottom line.

At this time, it is cut with care that the polarizing plate 13 is not cut off from the side of the release film 17, and it is confirmed that the distance of the cut portion of the release film 17 is 15 mm from the line below the cutout of the polarizing plate 13.

Next, the specimen is mounted on an autograpper (peeler), and the strength of the release film 17 is peeled off at a rate of 1.0 m / min. The maximum intensity of the measured intensity is defined as the surface slip intensity.

The peeling of the release film (17) in contact with the pressure-sensitive adhesive layer (15) during peeling is performed while pulling in the direction of 0 DEG. The 0 DEG direction means that the release film 17 slips in the horizontal direction during cutting in the actual cutting process and means pulling the release film 17 while maintaining the longitudinal direction of the release film 17 when the release film 17 is peeled off .

Preferably, in the present invention, the pressure-sensitive adhesive layer (15) and the release film (17) are adjusted so that the surface slip strength is 2 to 5 N / 15 m. If the surface slip strength is less than the above range, the above-mentioned effects (stains and curls) can not be secured sufficiently. On the contrary, if the surface slip intensity is out of the above range, the release film 17 and the polarizer 13 And therefore, it is appropriately used within the above range.

On the other hand, the release film according to the present invention can be any material that can satisfy the surface slip strength, and is not particularly limited.

Preferably, a release force of 0.035 to 0.040 N / 25 mm from the pressure-sensitive adhesive layer is used. The peeling force is an average peeling force measured in a range of 30 mm to 180 mm when a length of 200 mm is peeled by 180 ° at a speed of about 300 mm / min. If the peeling force is less than 0.02 N / 25 mm, there is a problem that the occurrence of peeling of the releasing film is increased when the peeling strength is higher than 0.05 N / 25 mm when the peeling force is bonded to the polarizing plate.

In the release film of the present invention, a silicone release agent coating composition containing a silicone compound is coated on one surface of a transparent base film, and heated, dried and cured to form a release coating layer. At this time, one surface is preferably a surface on the side in contact with the polarizing plate.

The base film may be a film excellent in transparency, mechanical strength, thermal stability, moisture barrier properties, isotropy, and the like. Specific examples include polyester resins such as polyethylene terephthalate, polyethylene isophthalate, polyethylene naphthalate and polybutylene terephthalate; Cellulose-based resins such as diacetylcellulose and triacetylcellulose; Polycarbonate resin; Acrylic resins such as polymethyl (meth) acrylate and polyethyl (meth) acrylate; Styrene resins such as polystyrene and acrylonitrile-styrene copolymer; Polyolefin resins such as polyethylene, polypropylene, cyclo- or norbornene-structured polyolefins, ethylene-propylene copolymers; Vinyl chloride resin; Amide resins such as nylon and aromatic polyamide; Imide resin; Polyether sulfone type resin; Sulfone based resin; Polyether sulfone type resin; Polyether ether ketone resin; A sulfided polyphenylene resin; Vinyl alcohol type resin; Vinylidene chloride resins; Vinyl butyral resin; Allylate series resin; Polyoxymethylene type resin; Epoxy resin, and the like, and a film composed of the thermoplastic resin blend may also be used.

Further, a film made of a thermosetting resin such as (meth) acrylic, urethane, acrylic urethane, epoxy, or silicone or a film made of an ultraviolet curable resin may be used.

The silicone release agent coating liquid composition comprises a silicone resin containing a polyorganosiloxane and a hydrogensiloxane and a catalyst.

The silicone resin is formed by a cross-linking reaction of a polyorganosiloxane and a hydrogensiloxane. The crosslinking reaction may be crosslinked through any one reaction system selected from the group consisting of a condensation reaction system, an addition reaction system and an ultraviolet ray or electron beam curing system.

The degree of polymerization of the silicone resin is preferably from 50 to 200,000, more preferably from 100 to 50,000.

When the degree of polymerization is less than 50, the molecular weight of the resin is too low to cause wettability failure that does not cover the entire surface of the substrate during coating. When the molecular weight exceeds 200,000, the molecular weight of the resin is too high, The coating thickness non-uniformity is undesirably caused.

The polyorganosiloxane has a low polarity and imparts an antistatic property to the release film, thereby preventing the foreign matter from being mixed and securing the optical safety and peeling uniformity. The polyorganosiloxane preferably has an alkenyl group as a functional group, and the alkenyl functional group may be a vinyl group, a hexenyl group, an acrylic group or a mixed functional group thereof. Hexenyl groups are more preferable considering the properties such as the stability with time and the reactivity with Si-H groups of the silicone release coating liquid composition.

The polyorganosiloxane preferably has a weight average molecular weight (Mw) of 10,000 to 1,000,000, more preferably 13,000 to 700,000, and most preferably 15,000 to 600,000. If the weight average molecular weight is less than 10,000, there may arise a problem of coating properties such as frying (fraying) on the substrate during coating and poor leveling property. If the weight average molecular weight is more than 1,000,000, , There arises a problem of flatness of the coating layer due to a variation in the thickness of the coated surface, resulting in a difference in peel strength of the release film.

The hydrogensiloxane serving as a crosslinking agent is a straight-chain poly (methylhydrogen) siloxane having at least two silicon-bonded hydrogen atoms in a molecule and having, for example, a terminal group of trimethylsilyl or hydrogendimethylsilyl; A straight chain type copolymer comprising methylhydrogensiloxane having a terminal group of trimethylsilyl or hydrogendimethylsilyl as a repeating unit; And dimethylsiloxane having a terminal group of trimethylsilyl or hydrogendimethylsilyl as a repeating unit.

The hydrogensiloxane preferably has a weight average molecular weight (Mw) of 800 to 20,000, more preferably 900 to 17,000, and most preferably 1,000 to 15,000. When the weight average molecular weight is less than 800, the crosslinking reaction force is lowered to form a silicone coating layer. When the weight average molecular weight is more than 20,000, the crosslinking reaction force remains after the curing reaction, thereby affecting the change of the peeling force with time.

The hydrogensiloxane may be used in an amount of 0.1 to 10 parts by weight, preferably 0.5 to 7 parts by weight, based on 100 parts by weight of the polyorganosiloxane (based on the solids content). If the content is less than 0.1 part by weight, it is difficult to form a silicone coating layer because the Si-H group that is crosslinked with the alkenyl group of the polyorganosiloxane is insufficient and the reaction can not be performed. When the amount exceeds 10 parts by weight, There is a problem that the peel strength of the release film is increased because the peel strength stability is lowered.

The catalyst may be a platinum-based compound as a crosslinking accelerator that accelerates a crosslinking reaction between a polyorganosiloxane and a hydrogensiloxane.

As the platinum-based compound, for example, platinum in the form of fine particles, platinum in the form of fine particles adsorbed on a carbon powder carrier, chloroplatinic acid, alcohol-modified chloroplatinic acid, olefin complex of chloroplatinic acid, palladium and rhodium can be used.

The catalyst is preferably contained in an amount of 0.01 to 0.1 part by weight, more preferably 0.02 to 0.08 part by weight based on 100 parts by weight of the silicone resin. If the content is less than 0.01 part by weight, the silicone release agent tends to be contaminated with the pressure-sensitive adhesive due to uncured cured product, resulting in deterioration of adhesion. If the content exceeds 0.1 parts by weight,

The silicone release coating liquid is prepared so that the concentration of the total solid content is 0.5 to 10% by weight. If the concentration is less than 0.5% by weight, coating defects such as insufficient presence of silicone resin on the surface of the substrate after coating drying occur, and when the concentration exceeds 10% by weight, viscosity of the coating solution increases rapidly, have.

The silicone release coating liquid is applied in an amount of 0.05 to 2.0 g / m 2, more preferably 0.07 to 1.5 g / m 2, and the thickness of the coating layer is adjusted to 5 to 150 nm after drying.

In addition, the release agent coating composition of the present invention may further comprise a polyol.

The polyol improves the cohesive force between the polyorganosiloxane and the hydrogensiloxane, which is a crosslinking agent, to maintain the adhesive force even in a harsh state and to improve the adhesion with the substrate, and is not particularly limited as long as it has two or more hydroxyl groups in one molecule Do not.

As the polyol, for example, at least one selected from the group consisting of a polyacryl polyol, a polyether polyol, a polyester polyol, a polycarbonate polyol and a polycaprolactone polyol can be used.

As the polyacrylic polyol, an acrylic copolymer in which (meth) acrylic acid ester alone or a copolymerized monomer having a (meth) acrylic acid ester and a hydroxyl group is copolymerized can be used. Examples of the copolymerizable monomer having a hydroxyl group include acrylic acid such as? -Hydroxyethyl acrylate,? -Hydroxypropyl acrylate, 3-hydroxypropyl acrylate,? -Hydroxybutyl acrylate, 4-hydroxybutyl acrylate and? -Hydroxypentyl acrylate Hydroxyalkyl esters such as hydroxyalkyl esters or methacrylic acid; A polyol such as a monoester of acrylic acid or a methacrylic acid monoester of polyhydric alcohol, N-methylol acrylamide, N-methylol methacrylamide, or a copolymer thereof of polyhydric alcohol such as glycerin and trimethylolpropane may be used.

The polyether polyol may be a copolymer of polyethylene glycol, 1,2-polypropylene glycol, polytetramethylene glycol, 1,2-polybutylene glycol, or the like with each polyol; Examples of the polyester polyol include ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, polytetramethylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6- Isophthalic acid, terephthalic acid, maleic acid, fumaric acid, adipic acid, sebacic acid, sebacic acid, isophthalic acid, isophthalic acid, A polyester polyol in the form of an acid such as azelic acid or a copolymer thereof may be used.

As the polycarbonate polyol, 1,6-hexane polycarbonate can be used. As the polycaprolactone polyol,? -Caprolactone and ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, 1,3-butanediol, 4-butanediol, polytetramethylene glycol, 1,2-polybutylene glycol, 1,6-hexanediol, neopentyl glycol and 1,4-cyclohexanedimethanol may be used.

The polyol preferably has a weight average molecular weight (Mw) of 200 to 4000. If the weight average molecular weight is less than 200, the rigidity is high and the rigidity and physical properties may be weak. When the weight average molecular weight is more than 4000, the rigidity is low and the physical properties such as strength as the fixing material are low.

The polyol may be appropriately mixed with additives such as polypropylene glycol (PPG), bisphenol-based diol (BP, BPE) or a mixture thereof in order to maintain proper physical properties for adhesion to the substrate. The additive may be added in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the polyol.

The polyol is preferably contained in an amount of 0.1 to 10 parts by weight, more preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the silicone resin. If the amount is more than 10 parts by weight, excess OH groups will remain and the stability with time will be lowered, thereby increasing the peeling force of the release film Lt; / RTI >

The release coating liquid composition for the release film may be applied by a known method such as a bar coating method, a doctor blade method, a reverse roll coating method, or a gravure roll coating method.

In addition, drying of the coating film and curing such as thermal curing or ultraviolet curing can be carried out individually or simultaneously. It is preferable that the reaction is carried out at 100 DEG C or higher. Drying and thermosetting are preferably carried out at 100 DEG C or higher for 30 seconds. If the drying temperature is 100 ° C or less and the time is 30 seconds or less, the curing of the coating film is incomplete and the problem of durability such as dropping of the coating film may occur

The pressure-sensitive adhesive layer in contact with the releasing film is not particularly limited in the present invention, and a known pressure-sensitive adhesive layer can be used, and any layer capable of satisfying the above-described surface slip strength can be used.

The pressure-sensitive adhesive layer may be a coating layer of an acrylic type, a silicone type, a rubber type, a urethane type, a polyester type or an epoxy type copolymer, preferably an acrylic copolymer, more preferably a pressure-sensitive acrylic pressure-sensitive adhesive. At this time, the pressure sensitive adhesive composition may contain a known antistatic agent such as an alkali metal salt, an ionic compound, a conductive polymer, a metal oxide, or a CNT (carbon nanotube). Among them, it is more preferable to include an ionic compound. Preferably, the pressure-sensitive adhesive layer comprises a copolymer containing a crosslinkable functional group, a crosslinking agent and a silane coupling agent.

The polarizing plate of the present invention can be manufactured by including the release film and the pressure-sensitive adhesive layer. For example, the surface protective film, the polarizing plate, the pressure-sensitive adhesive layer, and the release film may be stacked in this order as shown in Fig.

The polarizing plate is a multilayer film in which one polarizer and a transparent protective film are laminated on at least one side thereof.

The polarizer is a film comprising a polyvinyl alcohol-based resin in which a dichroic dye is adsorbed and oriented.

These polyvinyl alcohol resins may be modified, and for example, polyvinylformal modified with aldehydes, polyvinyl acetal, polyvinyl butyral and the like may be used. Normally, an unoriented film of a polyvinyl alcohol-based resin having a thickness of 20 to 100 mu m, preferably 30 to 80 mu m is used as a disk of a polarizing film.

The polarizer usually has a step of uniaxially stretching a polyvinyl alcohol resin film, a step of dyeing the stretched film with a dichroic dye to adsorb the dye, a step of treating the dye-adsorbed film with an aqueous solution of boric acid, Can be prepared through the process. At this time, iodine or dichroic organic dyes can be used as the dichroic dye.

The transparent protective film may be, for example, a film comprising an acetylcellulose resin such as triacetylcellulose or diacetylcellulose, a film containing a polyester resin such as polyethylene terephthalate, polyethylene naphthalate or polybutylene terephthalate, A film containing a carbonate-based resin, a film containing a cycloolefin-based resin containing a cyclic olefin such as norbornene as a main monomer, and the like. Examples of commercially available thermoplastic cycloolefin resins include Topas sold by Ticona of Germany, Aton sold by JSR Corp., Zono sold by Nippon Zeon Co., And Arpels (all trade names) sold by Mitsui Chemicals, Inc. When a protective film is formed from such a cycloolefin-based resin, known methods such as solvent casting method and melt extrusion method are suitably used for film formation. The formed cycloolefin resin film is also commercially available, for example, Essenina SCA40 sold by Sekisui Chemical Co., Ltd., and the like.

The polarizer and the transparent protective film are bonded through an adhesive.

As the adhesive, an aqueous adhesive such as an isocyanate adhesive, a polyvinyl alcohol adhesive, a gelatin adhesive, a vinyl polymer latex adhesive, a water-soluble polyester adhesive, and a urethane adhesive having a hydrophilic group may be used. Can be used.

The surface protective film is the above protective film or a protective film which is subjected to a treatment for hard coat treatment, antireflection treatment, anti-sticking, diffusion or anti-glare is used.

In addition, the polarizing plate may further include a known optical functional film.

Examples of the optically functional film include an optical compensation film in which a liquid crystal compound or a polymer compound thereof is oriented on the surface of a base material, a reflection type film that transmits polarized light of any kind, A polarizing separating film, a retardation film containing a polycarbonate resin, a retardation film containing a cyclic polyolefin resin, an antireflection functional film having a concavo-convex shape on its surface, an additional film having antireflection treatment on its surface, , And a transflective film having both a reflecting function and a transmitting function. One or two or more of these optical functional films can be laminated and used.

The polarizing plate having the above-described structure is manufactured in the form that a release film is attached to one side, and the manufacturing method thereof is not particularly limited in the present invention.

For example, a polarizing plate having a release film on one side may be manufactured by separately manufacturing a polarizing plate and a pressure-sensitive adhesive layer having a release film, and then attaching a pressure-sensitive adhesive layer to the polarizing plate while removing one of the release films.

The polarizing plate according to the present invention is applied to various display devices. At this time, the polarizing plate may have a structure in which at least one of an optical film, a reflector, a transflective plate, a viewing angle compensation film, and a brightness enhancement film such as a polarization conversion device used for forming a display device is laminated with an optical layer. More specifically, the present invention relates to a polarizing plate having a structure in which a protective film is laminated on one surface of a polarizer, which comprises a reflective polarizing plate or a transflective polarizing plate in which a reflector or a transflective reflector is laminated on a laminated protective film; An elliptic or circular polarizer in which a retarder is stacked; A wide viewing angle polarizer in which a viewing angle compensation layer or a viewing angle compensation film is laminated; Or a polarizing plate in which a brightness enhancement film is laminated.

The above-mentioned display device is preferably a liquid crystal display device.

In this case, the liquid crystal display device is not particularly limited, and liquid crystal display devices of various driving methods such as reflective type, transmissive type and transflective type liquid crystal display (LCD) and TN type, STN type, OCB type, HAN type, VA type, Device (LCD) can be preferably used.

In the present invention, since the liquid crystal display device is well known to those skilled in the art, detailed description of each configuration will be omitted.

[Example]

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention. Such variations and modifications are intended to be within the scope of the appended claims.

Example  1: Production of polarizing plate

(1) Production of Polarizer

A TAC film subjected to a saponification treatment and having a thickness of 40 占 퐉 was coated on both surfaces of a polarizer (polyvinyl alcohol resin film having a thickness of 23 占 퐉) with a modified polyvinyl alcohol (trade name Kossefaima Z200, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) and sodium glyoxylate 10% (SPM-01, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) and water in a weight ratio of 3/3/100 were fed at a discharge rate of 45 g / min. And dried to prepare a polarizing plate.

(2) Production of release film on which a sheet-like pressure-sensitive adhesive was formed

100 parts by weight of a (meth) acrylic acid ester copolymer (based on solid content) of butyl acrylate, acrylic acid, 2-hydroxyethyl acrylate 98; 1; 1 and having a weight average molecular weight of 1,300,000, 100 parts by weight of Coronate- (Based on solid content) and 0.1 part by weight of 3-glycidoxypropyltrimethoxysilane as a silane coupling agent were added to prepare a pressure-sensitive adhesive composition.

This was coated on the release-treated surface of a polyethylene terephthalate film (trade name "SP-PLR382050" manufactured by LINTEC CORPORATION) having a thickness of 38 μm provided with releasing treatment so as to have a thickness of 20 μm after drying with a die coater, A release film on which a pressure-sensitive adhesive was formed was prepared.

At this time, the release force of the release film was 0.035 N / 25 mm.

(3) Production of Polarizer with Release Film

The release film obtained above was bonded to the acetylcellulose film side of the polarizing plate by a laminator and cured for 7 days at a temperature of 23 캜 and a relative humidity of 65% to prepare a polarizing plate having a releasing film / pressure-sensitive adhesive layer on one side .

Example  2

A polarizing plate was produced in the same manner as in Example 1 except that a release film having a peeling force of 0.033 N / 25 mm was used.

Example  3

A polarizing plate was produced in the same manner as in Example 1 except that a release film having a peeling force of 0.040 N / 25 mm was used.

Comparative Example 1

A polarizing plate was produced in the same manner as in Example 1 except that a release film having a peel force of 0.025 N / 25 mm was used.

Comparative Example 2

A polarizing plate was produced in the same manner as in Example 1 except that a release film having a peel force of 0.030 N / 25 mm was used.

Comparative Example 3

A polarizing plate was produced in the same manner as in Example 1 except that a release film having a peel force of 0.045 N / 25 mm was used.

Comparative Example 4

A polarizing plate was produced in the same manner as in Example 1 except that a release film having a peeling force of 0.050 N / 25 mm was used.

Comparative Example 5

A polarizing plate was produced in the same manner as in Example 1 except that a release film having a peeling force of 0.055 N / 25 mm was used.

Comparative Example 6

A polarizing plate was produced in the same manner as in Example 1 except that a release film having a peeling force of 0.060 N / 25 mm was used.

Experimental Example  1: Measurement of physical properties

(1) Surface Slip strength measurement

The polarizing plate prepared in the above Examples and Comparative Examples was cut into a size of 15 mm x 130 mm (width * length) to prepare specimens. Two lines were drawn in parallel with the short sides at intervals of 15 mm, Were cut with a cutter.

Next, only the release film was cut along the parallel line indicated on the test piece. At this time, it was confirmed that the distance of the cut portion of the release film was 15 mm on the line below the polarizer cut portion.

Next, the specimen was mounted on an autograft (peeler), and the maximum strength was measured while peeling at a speed of 1.0 m / min.

(2) Evaluation of stain

The polarizing plate produced in the above Examples and Comparative Examples was cut into a size of 300 mm x 200 mm and left for 1 hour under constant temperature and humidity conditions and left for 24 hours in order to observe the effect of aging. The appearance was observed, Respectively.

<Evaluation Criteria>

○: The stain Missy.

B: Slight stain occurred (unrecognized at cross test)

×: occurrence of stain (visibility at the time of cross examination)

 (3) Excise assessment

The polarizer produced in the above Examples and Comparative Examples was cut into a size of 300 mm x 200 mm, and then it was confirmed whether or not the end of the polarizer was lifted. The knife movement speed was 5m / min and the press pressure was maintained at 10Mpa during cutting.

<Evaluation Criteria>

○: End lift occurred after cutting.

X: No problem after cutting

(4) Deviation evaluation

The polarizing plate produced in the above Examples and Comparative Examples was cut into a size of 300 mm x 200 mm, and then the end face polishing process of the polarizing plate was performed and the cross section was observed through an optical microscope to evaluate the degree of misalignment based on the following criteria.

<Evaluation Criteria>

○: No deviation

?: Dislocated (0 to 500 m)

X: Deviation (500 占 퐉 or more)

Release film peeling force
(N / 25 mm) Surface slip strength (N / 15 mm) Stain occurrence Occurrence Deviation evaluation After 1 hour After 24 hours Example 1 0.035 3.12 ○ ○ ○ ○ Example 2 0.033 2.35 ○ ○ ○ ○ Example 3 0.040 4.59 ○ ○ ○ ○ Comparative Example 1 0.025 0.82 ○ ○ × × Comparative Example 2 0.030 1.76 ○ ○ × × Comparative Example 3 0.045 5.12 △ × ○ ○ Comparative Example 4 0.050 7.08 × × ○ ○ Comparative Example 5 0.055 12.27 × × ○ ○ Comparative Example 6 0.060 22.69 × × ○ ○

Referring to Table 1, in the case of the release film having the surface slip intensity range proposed in the present invention, no unevenness was observed at the time of cutting the polarizing plate, and excellent results were obtained in evaluation of lifting or displacement.

In comparison, in Comparative Examples 1 and 2 in which the surface slip strength was less than 2 N / 15 mm, spots occurred, and in Comparative Example 1 in which the surface slip strength was low, it was confirmed that extreme displacement and displacement occurred significantly.

In the case of Comparative Examples 3 to 6 in which the surface slip strength exceeded 5 N / 15 mm, the floatation and deviation evaluation was good, but the stain occurred seriously.

From these results, it can be predicted that the process margin of the polarizing plate can be increased by controlling the surface slip intensity.

The release film for a polarizing plate according to the present invention is applicable to various display devices.

11: release film 13: pressure-sensitive adhesive layer
15: Polarizing plate 17: Surface protective film
51: Cutter

Claims (5)

And a surface slip strength with the pressure-sensitive adhesive layer of 2 to 5 N / 15 m. The release film for a polarizing plate according to claim 1, wherein the surface slip intensity is a maximum intensity measured by stripping the release film laminated on the pressure-sensitive adhesive layer at a rate of 1.0 m / min in the direction of 0 DEG. The release film for a polarizing plate according to claim 1, wherein the releasing film for the polarizing plate has a peeling force with respect to the pressure-sensitive adhesive layer of 0.035 to 0.040 N / 25 mm. The release film for a polarizing plate according to claim 1, wherein the release film for polarizing plate has a silicone release coating layer formed on one surface of the base film. A polarizing plate having a release film for a polarizing plate according to any one of claims 1 to 4 attached to one side thereof.

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